Furnace control



Sept. 5, 1944- w. E. FIREHAMMER FURNACE CONTROL Filed March 30. 1942 INVENTOR WELTON E.FIREHAMMER ATTORNEYS Patented Sept. 5, 1944 UNITED STAT ES PATENT "OFFICE FURNACE; CONTRO WeIton E. Fireha nmer, LOshkosh, Wis. Application March 30, 1942,8erial No. 436,749 Claims. (o1. 12c 2s5) This invention appertains to smokepipe dampers; and more particularly to furnace dampers of the general character shown in my Patent No. 2,179,120, issued November 7, 1939, and in my application Serial No. 298,679, filed October 9, 1939; now matured into Patent No; 2,259,973, issued October 21, 1941.

One of the primary objects of my present invention is the provision of novelmeans for, operating the damper gate from its inner face and directly from a lift arm, whereby the necessity.

of employing swinging levers and the like is dispensed with.

Another salient object of my invention is to provide novel means for forming the lift arm in suchamanner that no binding action will take place between the arm and the damper, and

whereby to permit the damper gate to open with a comparatively slight movement of the lift arm and with a progressively accelerated motion.

A further important object of my invention is to provide means operating in direct conjunction with the lift arm for checking or delaying the opening movement of the damper, said means including a dashpot having a check valve and a sleeve, the active size of which can be governed for accurate control.

A still further object of my invention is the provision of novel means for associating the weights with the damper gate, whereby the Weights can be accurately set for balancing the dampen and whereby the weights'will be spaced a maximum distance. fromthe center of the gate for eliminating torque, etc.

Withthese and other objects in view, the invention consists in the novel construction, arrangement, and formation of parts, as will be hereinafter more specifically described, claimed, and illustrated in the accompanying drawing, in which drawing:

Figure 1 is a central, vertical, sectional view through my improved damper control, the view being taken on the line l'| of Figure 2, looking in the direction of the arrows.

Figure 2 is a .view partly in section and partly in plan, the; section being taken substantially. on

the line 2-2 of Figure 1, looking in the direction of the arrows.

Figure 3 is a detail sectional view taken on the line 3-3 of Figure 1, illustrating the connection between the lift arm and the roller bracket on the damper.

Figure 4 is an enlarged, fragmentary, detail, sectional view .illustrating the dashpot or check mechanism for the damper.

Referring to the drawing indetail, wherein similar reference characters designate corresponding parts throughout the several views, the numeral 5 generally indicates my improved device, and the same includes an annular damper ring or frame .6, which is securely fastened to a breach pipe I, which can be connected to an intermediate part of a smokepipe leading from any suitable heating plant or'the like.

The fastening means for securing the ring 6 to the pipe I can consist of fastening screws 8. Likewise, the periphery of the ring can be rabbeted to receive the pipe. The extreme lower end of: the ring or frame 6 has formed thereon a depending foot 9 to which is fastened a bracket Hl for supporting the various operating parts of the damper actuating mechanism and the easing. ll for said mechanism. As is clearly shown in Figures 1 and 2, the bracket Ill isin the nature of a laterally extending plate and forms a cover for'the casing ll. Screws I2 can be employed for 'detachably connecting the casing to said bracket plate.

Rockably mounted within the ring or frame 6 is .the damper gate or plate I3. This gate can be formed from sheet metal, and the periphery thereof is inturned to provide a reinforcing flange l4. Bearing blocks I 5 are secured tothe inner face of the damper gate at a point above its horizontal diametric centeryand the outer ends of the bearing blocks receive the pointed bearing terminals of adjustable pintles l6 carried by the annular damper ring or frame .6. V

Due to the mounting of the damper gate [3, it can be seen that the bottom of the gate overbalances the upper end of the gate, and, hence, the damper gate normally tends to swing to a closed position. However, in order to accurately balance and set the damper gate to suit various drafts, atmospheric pressures, etc., for different stacks and pipes, the gate has adjustably associated therewith above its pivot point weights I'l. These weights I! are mounted upon a cross bolt [8,,which extends through a vertical slot IS in said gate, and by tightening the bolt, the weights l7 can'be set to a selected desired position. The gate below its horizontal center and adjacent its periphery hassecured thereto an inwardly extending threaded rod 20,. and a weight 2 is adjustably mounted on said rod. Hence, by adjusting the weights I l and 2|, the damper gate can be accurately balanced to suit varying conditioris, and attention is directed to the fact'that the weights are located/as far awayfrom the horizontal center of the gate as is practicable, so

as to reduce torque and the like during movement of the gate.

In order to liimt the outward swinging movement of the lower end of the damper gate, a resilient cushion 22 can be secured to the bracket l and arranged in the path of the lower end of said gate.

The operating mechanism for the damper gate includes a solenoid 23 having a vertically slidable plunger 24. The solenoid is bolted to a U-shaped bracket 25, which is slidably mounted on a guide rod 26, which depends from the bracket ID. A

suitable stop 21 limits the downward movement of the U-shaped bracket 25 on the guide rod, and the bracket 25 is normally urged toward said stop by a spring 28, which is coiled about the rod. The lower end of the spring bears against the upper end of the bracket, and the upper end of the spring engages a washer 29, the upward movement of which is limited by a stop 30. The plunger-or movable core 24 of the solenoid has rigidly, but adjustably, fastened thereto an upstanding operating rod 3|, and this rod is slidably mounted in a guide sleeve 32, which is formed on the bracket l0.

Connected to the upper end of the operating rod 3| by a coupling 33 is the operating arm 34. This operating arm is of an angle-shape and includes a horizontal portion 35, which extends through a slot 36 in th damper gate l3. The slot 35 is disposed below the pivot point of the gate and its extreme inner end is arranged on the inner side of the gate andis bent to form an upwardly extending angular extension 31. Fastened to the inner face of the damper gate below the pivot point of said gate is a depending bracket 38 carrying an anti-friction roller 39, which engages the upper surface of the lift arm 34.

Also fastened to the plunger or core 24 of the solenoid is a transversely extending rod.40 having attached to its opposite ends upwardly extending contractile coil springs 4|. These springs extend through guide openings formed in the opposite sides of the sleeve 32, and the upper ends of the springs 4| are secured to threaded rods or bolts 42 adjustably supported by the upper end of the sleeve 32. These springs normally tend to pull up on the plunger, and, hence, raise the slide rod 3| and the lift arm 34.

When the arm 34 is lifted, the same pushes up on the anti-friction roller 39 and the bracket 38, and, consequently, swings open the damper gate. As the roller engages the upwardly inclined extension 31 of said arm, the gate will be further opened with an accelerated motion.

By this construction and arrangement, I am permitted to operate the gate from the inner face thereof and with the use of a simple lift arm. By varying the angularity of the extension 31, the amount of opening of the gate can be changed.

Obviously, when the solenoid 23 is energized, the lift arm is pulled down away from the antifriction roller 39, and, hence, the weight 2| is free to move the damper gate to its closed position, and the damper gate can then actuate automatically under the influence of stack drafts, atmospheric pressures, etc. I a

While I have not shown, the solenoid in the motor circuit of a coal stoker or oil burner, it is to be understood that the solenoid can be arranged in such circuits (see my patent above mentioned).

Thus, when the circuit to the motor for the feed of coal or oil is closed, the solenoid is energized and the damper gate will have a tendency to move to its closed position, and when the stoker or oil feed is not in operation, the solenoid is deener-gized, and the damper gate is free to swing open to check the draft.

As the weights l1 and 2| are independent of one another, the said weights can be readily adjusted and set for any draft value.

In order to retard or check the upward movement of the rod 3| and the lift arm 34 under the influence of the springs 4|, I provide a dashpot mechanism 43. This mechanism includes a cylinder 44, which can be case on the bracket l0, and this cylinder, in effect, forms a part of the guide sleeve 32. The upper end of the cylinder is closed by an inwardly opening check valve 45. A bleed passageway 46 opens out through the upper end of the cylinder, and the active size of this bleedpassageway or orifice can be controlled by a set screw 41.

Slidably mounted within the cylinder 44 is a piston 48, and this piston has connected therewith a piston rod 49. The piston rod 49 is, in turn, connected with the operating rod 3| by a connecting strap 50. This strap 50 is secured to the rod 3| by means of suitable clamp nuts. Similar clamp nuts are employed on the piston rod 49 for connecting the strap 53 with the piston rod, and the rod 49 can be raised and lowered within certain limits relative to the strap by means of said clamp nuts.

By varying the size of the orifice or bleed port 46, the time of the delay of the checking of the draft can be controlled, and upward movement of the rod 3| under influence of its springs 4| is checked by the movement of the piston or plunger 48 acting against the trapped air in the cylinder. Obviously, the sides of the port 46 can be accurately controlled by adjusting the screw 41.

If desired, the rod 3| and the lift arm 34 can swing free on the plunger 24, in view of the fact that th slot 36 will form an effective guide for said lift arm during the raising and lowering thereof.

From the foregoing description it can be seen that I have provided an exceptionally simple and positive mechanism for operating the check damper gate I3, with means for controlling the opening movement of the damper.

Changes in details may be made without departing from the spirit or the scope of this invention, but what I claim as new is:

1. In a furnace control of the type having a supporting frame, a damper gate and means rockably supporting the damper gate in the frame above its horizontal diametric center, said gate having a slot therein; a vertically movable lift arm having a portion extending through said slot beyond the inner face of the damper gate, and a bracket on the inner face of said damper gate engaging the portion of the lift arm extending beyond the inner face of the gate.

2. In a furnace control of the type havin a supporting frame, damper gate, and means rockably supporting the damper gate in the frame above its horizontal diametric center, said gate having a slot therein; a vertically movable lift arm having a portion extending through said slot beyond the inner face of the damper gate and a roller bracket on the inner face of said damper gate below the pivot point of the damper gate engaging the portion of the lift arm extending through the slot.

3. In a frame control of the type having a supporting frame, a damper gate, and means rockably supporting the damper gate in the frame above its horizontal diametric center, said gate having a slot therein; a vertically movable lift arm having a substantially horizontal portion extending through said slot beyond the inner face of the damper gate and an upwardly and rearwardly inclined terminal portion, and a bracket on the inner face of the damper gate initially engaging the horizontal portion and then the inclined portion upon the opening of the damper gate.

4. In a furnace control of the type having a frame, a damper gate, and means rockably supporting the gate in the frame above its horizontal diametric center; a vertically movable lift arm having a portion thereof extending beyond the inner face of the damper gate, a bracket secured to the inner face of the gate below the pivot point of said gate for contact with said mentioned portion of the lift arm, spring means norm ally tending to raise the lift arm for opening "the gate,

means for lowering the lift arm against the tension of said spring means, and means for limiting the closing movement of the gate.

, 5. In a furnace control of the type having a frame, a damper gate, and means rockably supporting the gate in the frame above its horizontal diametric center; a vertically movable lift arm having a portion thereof extending beyond the inner face of the damper gate, a bracket secured to the inner face of the gate below the pivot point of said gate for contact with said mentioned portion of the lift arm, spring means normally tending to raise the lift arm for opening the gate, means for lowering the lift arm against the tension of said spring means, and means for limiting the closing movement of the gate, and means for checking the upward movement of the lift arm under the tension of said sp ring means.

WELTON E. FIREHAMMER. 

